UVA 11468 Substring

Test instructions: give you k a template string, then give you some probability of the occurrence of characters, then give you a length l, ask you these characters are composed of the length of the string does not contain any one template string probability.

Idea: AC automata + Introduction DP

First, a good AC automaton is constructed with K templates. The topic said that the new string of long L does not contain any K-string, in fact, is said in the structure of the tree, from the root down the L step does not contain K templates. Whether the question is a K template string with the match tag.

The state transfer equation code is commented out.

1#include <cstdio>2#include <cstring>3#include <queue>4#include <cstdio>5#include <map>6#include <string>7 using namespacestd;8 9 Const intSigma_size = -;Ten Const intMaxnode = -;//Total node points One Const intMaxs = -+Ten;//Number of templates A  - intidx[ the], N; - DoubleProb[sigma_size]; the  - structAhocorasickautomata - { -     intCh[maxnode][sigma_size]; +     intF[maxnode];//fail function -     intMatch[maxnode];//whether to include a string +     intSz//Total node points A  at     voidInit () -     { -SZ =1; -memset (ch[0],0,sizeof(ch[0])); -     } -  in     //Insert String -     voidInsertChar*s) to     { +         intU =0, n =strlen (s); -          for(inti =0; I < n; i++) the         { *             intc =Idx[s[i]]; $             if(!Ch[u][c])Panax Notoginseng             { -memset (Ch[sz],0,sizeof(Ch[sz])); theMATCH[SZ] =0; +CH[U][C] = sz++; A             } theU =Ch[u][c]; +         } -Match[u] =1; $     } $  -     //calculate the Fail function -     voidGetfail () the     { -queue<int>Q;Wuyif[0] =0; the         //Initialize Queue -          for(intc =0; c < sigma_size; C++) Wu         { -             intU = ch[0][c]; About             if(U) $             { -F[u] =0; - q.push (u); -             } A         } +         //fail calculation by BFS sequence the          while(!q.empty ()) -         { $             intR =Q.front (); the Q.pop (); the              for(intc =0; c < sigma_size; C++) the             { the                 intU =Ch[r][c]; -                 if(!u) in                 { theCH[R][C] =Ch[f[r]][c]; the                     Continue; About                 } the q.push (u); the                 intv =F[r]; the                  while(v &&!ch[v][c]) v =F[v]; +F[u] =Ch[v][c]; -Match[u] |=Match[f[u]]; the             }Bayi         } the     } the }; -  - ahocorasickautomata ac; the  the Doubled[maxnode][ the]; the intvis[maxnode][ the]; the  - DoubleGetprob (intUintL//D[u][l]=prob[u]*d[v][l-1] state-to-equation V for u son can walk node the { the     if(! Lreturn 1.0; the     if(Vis[u][l])94         returnD[u][l]; theVIS[U][L] =1; thed[u][l]=0.0; the      for(inti =0; I < n; i++)98         if(!Ac.match[ac.ch[u][i]]) AboutD[u][l] + = prob[i] * Getprob (Ac.ch[u][i], L-1); -     returnD[u][l];101 }102 103 Chars[ -][ -];104  the intMain ()106 {107     intT;108scanf"%d", &T);109      for(intKase =1; Kase <= T; kase++) the     {111         intK, L; thescanf"%d", &k);113          for(inti =0; I < K; i++) scanf ("%s", S[i]); thescanf"%d", &n); the          for(inti =0; I < n; i++) the         {117             Charch[9];118scanf"%S%LF", CH, &prob[i]);119idx[ch[0]] =i; -         }121 ac.init ();122          for(inti =0; I < K; i++) Ac.insert (S[i]);123 Ac.getfail ();124scanf"%d", &L); thememset (Vis,0,sizeof(Vis));126memset (D,0,sizeof(d));127printf"Case #%d:%.6lf\n", Kase, Getprob (0, L)); -     }129     return 0; the}

View Code

UVA 11468 Substring